Clinical Significance Of Circulating Tumor Cells In Patients With Small-cell Lung Cancer

Objective：This study detected the number of circulating tumor cells (CTCs) in peripheralblood before and after the first cycle of chemotherapy in patients with small cell lungcancer(SCLC), analyzed the relationship of CTCs with clinicopathologic characteristics andprogression-free survival(PFS) of small-cell lung cancer patients, further investigate theclinical application value of CTCs.Methods: Testing the number of CTCs in42SCLC patients’peripheral blood before and afterthe first cycle of chemotherapy by immunomagnetic negative separation andimmunohistochemistry method, and at the same time taking peripheral blood of the10casesof lung benign disease patients and10cases of healthy volunteers as control.Results:1.The positive rate of CTCs was76.19%in42SCLC patients but0%in the controlgroup respectively, being a significant difference.(2=31.492,P=0.000)；2.The positive rate of CTCs and SCLC patients’ gender, age, family history, smoking,distant metastases (liver, bone, brain, adrenal gland), carcinoembryonic antigen (CEA),cytokeratin19fragment(CYFRA21-1) were not statistically significant(P>0.05). Thepresence of CTCs was correlated positively with the SCLC patients’ ECOG score, clinicalstage, M stage, the number of metastatic sites, NSE value and LDH value，being a significantdifference(P<0.05).3.Before the first cycle of chemotherapy, the median PFS was6.055months and10.670months (χ2=7.081, P=0.008) for patients with CTCs-positive and CTCs-negative, respectively;After the first cycle of chemotherapy, the median PFS was4.862months and10.535months(χ2=25.657, P=0.000) for patients with CTCs-positive and CTCs-negative,respectively.4.Compared with SCLC patients before the first cycle of chemotherapy, the number ofCTCs decreased, increased and unchanged after one chemotherapy cycle were25cases,12cases and5cases, respectively. The median number of CTCs before and after chemotherapywere5and3.5, being a significant difference.5.The PFS of SCLC patients for CTCs-positive before the first cycle of chemotherapybut CTCs-negative after chemotherapy, CTCs-negative before chemotherapy butCTCs-positive after chemotherapy, both CTCs-positive before and after chemotherapy, bothCTCs-negative before and after chemotherapy, were9.050months,6.333months,4.661months,12.529months, respectively, being a significant difference of the four groups.6.Univariate analysis showed that: ECOG score, clinical stage, M stage, the number ofmetastatic sites, NSE value and LDH value, baseline CTCs number and the CTCs numberafter the first cycle of chemotherapy were related to PFS of SCLC patients(P <0.05); Multiplefactors analysis showed that stage, presence of distant metastasis and NSE levels wereindependent prognostic factors for PFS in patients with SCLC.Conclusion:1.There were significant differences for the positive rate of CTCs between SCLC patients and non-lung cancer.2.The positive rate of CTCs was related to the SCLC patients’ ECOG score, clinicalstage, M stage, the number of metastatic sites, NSE value and LDH value.3.The number of CTCs before and after the first cycle of chemotherapy can both predictthe PFS of the SCLC patients, and those patients with CTCs-negative after the first cycle ofchemotherapy could obtain a longer PFS.4.Patients with higher ECOG score, extensive stage, distant metastasis, more ofmetastatic sites, NSE≥25ng/m, LDH≥270U/L, both CTCs-positive before and after the firstchemotherapy had a shorter PFS, prompting that those factors could be poor prognosticfactors for SCLC patients.